Yes I agree whole heartedly, the tray table is a common and painful tech problem....especially when it is ALWAYS the F/O's table that has been removed (...I think they are interchangable.....).
Seriously though, I'm beginning to think that MTBF (Mean time between failures) on some components are accurate to the point that several similar components fail at once across the fleet. At the mo, we have a few SEC's (Spoiler/Elevator Computers) failed. Thats pretty common and the flavour of the month I think. Not a show stopper though......